KR19980085481A - New Soluble Polyimide Resin - Google Patents

Abstract

The present invention relates to a novel soluble polyimide resin and a method for preparing the same, and more particularly, to an aromatic diamine containing an aromatic tetracarboxylic dianhydride and an aliphatic ring group substituted with alkyl groups of various structures. The present invention relates to a new type of polyimide resin excellent in solubility and transparency and a method for producing the same.

That is, a new polyimide resin having excellent heat resistance and excellent dissolution properties was prepared by reacting with various kinds of aromatic carboxylic dianhydrides by using a diamine having a new structure as a monomer instead of the aromatic diamine used to prepare a polyimide resin. The resulting polymers exhibited a glass transition temperature of 250 to 400 ° C., and the solubility increased with increasing volume of the alkyl group. In addition, various organic solvents, especially THF and the like showed excellent dissolution properties that are easily dissolved even at room temperature.

Description

New Soluble Polyimide Resin

The present invention relates to a novel soluble polyimide resin and a method for preparing the same, and more particularly, to an aromatic diamine containing an aromatic tetracarboxylic dianhydride and an aliphatic ring group substituted with alkyl groups of various structures. The present invention relates to a novel polyimide resin having excellent solubility and transparency and having the following general formula (1) as a repeating unit, and a method for preparing the same.

[Formula 1]

In Chemical Formula 1,

Is , , , And One or more tetravalent groups selected from among them;

Is At least one substituted cyclohexylidene dianiline group represented by

, , , , And Two groups selected from among them may be included; Wherein R ³ represents a phenyl group substituted by straight or branched alkyl group of C ₁ ~ C ₆ linear or branched alkyl group, a phenyl group, or C ₁ ~ C ₆ a.

In general, the polyimide (hereinafter referred to as PI) resin refers to a high heat-resistant resin prepared by imidating an aromatic tetracarboxylic acid or a derivative thereof and an aromatic diamine or an aromatic diisocyanate. However, these PI resins have insolubility that does not dissolve in a solvent and insolubility that does not melt by heating.

In addition, the PI resin may have various molecular structures depending on the type of monomer used. Generally, pyromellitic dianhydride (PMDA) or biphenyltetracarboxylic dianhydride (BPDA) is used as an aromatic tetracarboxylic acid component, and oxydianiline (ODA) or p-phenylene diamine is used as an aromatic diamine component. It is prepared by condensation polymerization using (p-PDA), and the most typical PI resin has the following formula (10) as a repeating unit.

[Formula 10]

The PI resin having the above formula (10) as a repeating unit is an insoluble and insoluble ultra high heat resistant resin, which has the following characteristics: (1) excellent thermal oxidation resistance, (2) extremely high usable temperature, and long-term service temperature. 260 ℃, short term use temperature is 480 ℃, excellent heat resistance, (3) excellent electrochemical and mechanical properties, (4) good radiation and low temperature properties, (5) intrinsic flame retardancy, (6) Excellent chemical property.

However, the PI resin having the above formula (10) as a repeating unit has an advantage of having excellent heat resistance characteristics, while processing is very difficult due to the insoluble and insoluble properties.

As a method for improving the disadvantages of the PI resin, a method of introducing a polar group into the polymer backbone or a side chain, a method of introducing a bulky linking group or a pendant group, and increasing the flexibility of the polymer main chain How to make is reported.

In particular, as a study to increase the solubility of PI resin, T. Kurosaki et al. Have published a method for preparing a soluble PI coating solution using alicyclic anhydride as a monomer [Macro molecules, 1994, 27. , 1117 and 1993, 26, 4961]. In addition, in 1993, Qn Jin et al. Produced soluble PI resins using cyclic diamines [J.P.S. Part A. Polym. Chem. Ed., 31, 2345-2351]

However, most of the soluble PI resins modified by the above method have the advantage of improved solubility due to the increased flexibility of the chain. Has a problem.

In addition, the representative soluble PI resin (Matrimid 5218) developed by Ciba Geigy, reported to provide excellent heat resistance and excellent dissolution characteristics by introducing trimethylindane group into the polymer main chain. have. However, since these PI resins have to go through several steps in the preparation of monomers, there are many restrictions on their universal use.

As part of such research, the present inventors have studied to improve the dissolution and melting characteristics of polyamideimide resin, which is a representative thermoplastic high heat resistant resin, through the past years for improving processing characteristics of existing aromatic high heat resistant polymers. Was performed. As a result, it is found that the solubility of the polymer can be greatly increased by introducing an isophorone diamine (hereinafter referred to as IPDA), an aliphatic diamine compound containing a trimethylcyclohexyl group, into the main chain of the polymer. [US Patent No. 5,521,276].

In addition, the present inventors endeavored to prepare a PI resin which is more excellent in heat resistance and soluble than a PI resin containing IPDA, and as a result, trimethylcyclohexylidene dianiline, which is an aromatic diamine compound containing trimethylcyclohexyl group, is produced. (Hereinafter, referred to as TMCH-DA) as a monomer, various types of single PI and copolymerized PI having excellent physical properties have also been patented (Korean Patent Application No. 97-2811).

Based on the above results, the present inventors introduced various different types of substituents into cyclohexylidene groups instead of the methyl group of trimethylcyclohexylidene group, which is a linking group between two phenyl groups of TMCH-DA. Heat resistance could be greatly increased.

The present invention introduces a new structure of aromatic diamine in place of the aromatic diamine used in the production of the existing PI resin, and reacts it with various kinds of aromatic tetracarboxylic dianhydrides to produce a new PI resin having excellent heat resistance and excellent dissolution characteristics. The present invention was completed by manufacturing.

Accordingly, the present invention provides a new soluble PI resin that can be used as a core heat-resistant material of high-tech industries such as electric, electronics, aerospace and aviation, with excellent molding and processability such as solubility while maintaining the properties of the existing PI resin. The purpose is.

The present invention is characterized by a polyimide resin having the following general formula (1) as a repeating unit.

Formula 1

In Chemical Formula 1, And Are as defined above, respectively.

In addition, the present invention is a method for producing a polyimide resin by solution polymerization of an aromatic tetracarboxylic dianhydride and an aromatic diamine compound,

Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride (PMDA), benzophenone tetracarboxylic dianhydride (BTDA), oxydiphthalic dianhydride (ODPA), and biphenyltetracarboxylic dianhydride (BPDA). , One or two or more selected from hexafluoroisopropylidenediphthalic dianhydride (HFDA) and hydroquinone bisphthalic dianhydride (HQDPA),

The aromatic diamine compound contains at least one of the substituted cyclohexylidene dianiline derivatives represented by the following formula (2) as essential components, and oxydianiline, methylenedianiline, m-bisaminophenoxydiphenylsulfone and para as necessary. It includes a method for producing a polyimide resin having a repeating unit of Formula 1 characterized in that it contains one or two or more compounds selected from bisaminophenoxydiphenyl sulfone.

[Formula 2]

In Formula 2, R ³ represents a C ₁ to C ₆ straight or branched alkyl group, a phenyl group, or a C ₁ to C ₆ straight or branched alkyl group substituted with a phenyl group.

Referring to the present invention in more detail as follows.

The present invention is a substituted cyclohexylidene dianiline derivative represented by Formula 2, for example, 4-methylcyclohexylidene dianiline (MECHDA), 4-ethylcyclohexylidene dianiline (ETCHDA), 4-t-butyl Formula 1 prepared by containing cyclohexylidene dianiline (TBCHDA), 4-amylcyclohexylidene dianiline (AMCHDA) and 4-phenyl-substituted cyclohexylidene dianiline (PHCHDA) as an essential component of the aromatic diamine compound The present invention relates to a PI resin having a repeating unit and a manufacturing method thereof.

PI resin according to the present invention has a weight average molecular weight (M _w ) of about 50,000 ~ 200,000 g / mol and maintains an intrinsic viscosity in the range of 0.5 ~ 2.0 dL / g, glass transition temperature (T _g of 250 ~ 400 ℃ ₎ )

In addition, the PI resin of the present invention includes m-cresol including aprotic polar solvents such as dimethylacetamide (DMAc), dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), acetone, and ethyl acetate. Easily dissolved at room temperature with respect to organic solvents such as. In addition, it exhibits high solubility of 10 wt% or more at room temperature for low boiling point solutions such as tetrahydrofuran (THF), chloroform, and low absorbing solvents such as γ-butyrolactone. Moreover, high solubility is shown also about these mixed solvents.

The present invention will be described in more detail based on the following examples, but the present invention is not limited thereto.

Example 1

4-methylcyclohexylidenedianiline (hereinafter referred to as MECHDA; 2.80 g, 0.01 mole) was slowly passed through nitrogen gas through a 50 ml reactor equipped with a stirrer, temperature controller, nitrogen injector, dropping funnel and cooler. After dissolving in 36 ml of dimethylacetamide (hereinafter referred to as DMAc) which is a reaction solvent, it is dissolved in m-cresol while passing nitrogen gas, and then solid pyromellitic dianhydride (hereinafter referred to as PMDA) while passing nitrogen gas. 2.18 g, 0.01 mole) was added slowly. At this time, the solid content (solid content) was fixed to 15% by weight and the reaction temperature was raised to 70 ℃ and the reaction was carried out for 2 hours. The temperature was then raised to reflux and stirred for 6-12 hours. At this time, isoquinoline (1 to 5% by weight) was used as the imidization catalyst. After the reaction was completed, the reaction mixture was precipitated in excess methanol (hereinafter referred to as MeOH) using a waring blender, and the filtered polymer was washed several times with water and MeOH. Drying under reduced pressure at temperature synthesized a new PI resin (hereinafter referred to as P-1). The yield of polymerization was quantitative. The intrinsic viscosity measured at 30 ° C. at a concentration of 0.5 g / dL using methacresol as a solvent was 1.18 dL / g.

Example 2

4-ethylcyclohexylidenedianiline (ETCHDA: 2.94 g, 0.01 mole) and PMDA (2.18 g, 0.01 mole) were dissolved in m-cresol, and then PI resin (hereinafter, P- 2) were synthesized. The PI resin thus prepared was dissolved in m-cresol at a concentration of 0.5 g / dL, and the inherent viscosity measured at 30 ° C. was 1.27 dL / g.

Example 3

4-t-butylcyclohexylidenedianiline (hereinafter referred to as TBCHDA: 3.22 g, 0.01 mole) and PMDA (2.18 g, 0.01 mole) were dissolved in m-cresol, followed by PI in the same manner as in Example 1. A resin (hereinafter referred to as P-3) was synthesized. The PI resin thus prepared was dissolved in m-cresol at a concentration of 0.5 g / dL, and the inherent viscosity measured at 30 ° C. was 0.93 dL / g.

Example 4

4-amylcyclohexylidenedianiline (hereinafter referred to as AMCHDA: 3.36 g, 0.01 mole) and PMDA (2.18 g, 0.01 mole) were dissolved in m-cresol, and then PI resin ( Hereinafter, P-4) was synthesized. The PI resin thus prepared was dissolved in m-cresol at a concentration of 0.5 g / dL, and the inherent viscosity measured at 30 ° C. was 1.24 dL / g.

Example 5

4-phenyl substituted cyclohexylidene dianiline (hereinafter referred to as PHCHDA: 3.40 g, 0.01 mole) and PMDA (2.18 g, 0.01 mole) in m-cresol, and then PI in the same manner as in Example 1 A resin (hereinafter referred to as P-5) was synthesized. The PI resin thus prepared was dissolved in m-cresol at a concentration of 0.5 g / dL, and the inherent viscosity measured at 30 ° C. was 0.80 dL / g.

Example 6

ETCHDA (2.21 g, 7.5 m mole) and oxydianiline (hereinafter referred to as ODA; 0.5 g, 2.5 mmol) were dissolved in m-cresol (34 mL), followed by addition of PMDA (2.18 g, 0.01 mole) and A copolymerized PI resin (hereinafter, referred to as P-6) was synthesized in the same manner as in Example 1. The PI resin thus prepared was dissolved in m-cresol at a concentration of 0.5 g / dL, and the inherent viscosity measured at 30 ° C. was 1.32 dL / g.

Comparative example

In the same manner as in Example 1, except that cyclohexylidenedianiline (hereinafter referred to as CHDA: 2.66 g, 0.01 mole) and PMDA (2.18 g, 0.01 mole) by reacting the PI resin (hereinafter, P) -7) were synthesized. The prepared PI resin precipitated in the solid phase during the reaction, and the inherent viscosity could not be measured because it was insoluble in m-cresol.

Experimental Example 1 Measurement of Molecular Weight

The film formability measurement results of the intrinsic viscosity and the solvent mold for each of the PI resins prepared in Examples 1 to 6 and Comparative Examples are shown in Table 1 below.

TABLE 1

polymer Intrinsic viscosity (dL / g) Film Formability by Solvent Molding Example 1 (P-1) 1.18 Jill Kim Example 2 (P-2) 1.27 Jill Kim Example 3 (P-3) 0.93 Jill Kim Example 4 (P-4) 1.24 Jill Kim Example 5 (P-5) 0.80 Jill Kim Example 6 (P-6) 1.32 Jill Kim

The PI resins prepared in Examples 1 to 6 according to the present invention were all amorphous transparent resins, and high molecular weight polymers having an intrinsic viscosity of about 0.5 to 2.0 dL / g as measured in m-cresol were obtained. Film formation by was also very good. That is, the diamine monomers of the present invention having a bent structure can be seen that a high molecular weight polymer can be produced by a one-step imidization reaction at a high temperature.

On the other hand, the PI resin prepared according to the comparative example was a poorly soluble resin, and it was impossible to measure the intrinsic viscosity in m-cresol.

Experimental Example 2 Thermal Analysis

In order to evaluate the thermal properties of each of the PI resins prepared in Examples 1 to 6 and Comparative Examples, the glass transition temperature and the pyrolysis temperature were measured.

The glass transition temperature was measured from the secondary thermal traces of the DSC measurement conducted by heating at a rate of 10 ° C./min under a nitrogen stream using a differential scanning calorimeter (DSC). The pyrolysis temperature was measured using a thermogravimetric analysis (TGA) while raising the temperature at a rate of 10 ° C./min under a nitrogen stream.

TABLE 2

Dianhydride diamine Glass transition temperature (℃) PMDA BPDA BTDA HFDA ODPA HQDPA MECHDA 349 355 346 306 300 267 ETCHDA - 336 - - - - PHCHDA - - 313 312 301 263 TBCHDA - 331 318 319 310 276 AMCHDA 348 342 318 310 298 261

As can be seen in Table 2, the novel polymers prepared in the present invention show a high glass transition temperature (T _g ) in the range of 250 to 400 ° C., although there are some differences depending on the type of anhydride and the substituent used. Given that Kapton ™, a representative wholly aromatic PI resin, exhibits a glass transition temperature around about 380 ° C., the present invention may have significant significance.

In other words, the PI resin according to the present invention exhibits long-term heat resistance that is inferior to Kapton ™, which has advantages in processing. That is, since the PI resin of the present invention is dissolved in the imidized state, it is not necessary to perform a separate imidization reaction after applying the resin solution, and the processing temperature can be lowered to 200 ° C or lower, which is the solvent evaporation temperature. Therefore, it is possible to prevent thermal aging of peripheral parts. In addition, there is an advantage that can reduce the bubble generation due to the generation of side reactions at a high temperature. Therefore, it can greatly contribute to expanding the applicability of PI resin in the future.

TABLE 3

Dianhydride diamine Pyrolysis Temperature (℃) PMDA BPDA BTDA HFDA ODPA HQDPA MECHDA 520 520 521 523 523 530 ETCHDA 512 526 497 516 520 510 PHCHDA 480 507 500 505 513 504 TBCHDA 519 505 500 523 525 528 AMCHDA 511 520 491 530 524 517

According to Table 3, the maximum reduction temperature of the PI resin prepared in the present invention was about 500 ° C., which was a very good value.

Experimental Example 3 Dissolution Characteristics

The dissolution characteristics of the organic resin of the PI resin according to the present invention were measured and shown in Tables 4 and 5.

TABLE 4

Dissolution Characteristics of Pyromellitic Acid Anhydride (PMDA) PI Resin

Solvent Diamine Melting degree NMP DMSO TCE Dioxane THF CHCl ₃ CH ₂ Cl ₃ Acetone MECHDA ++ + ++ ++ - - - - ETCHDA ++ + ++ ++ ++ ++ ++ - PHCHDA ++ + ++ ++ ++ ++ ++ - TBCHDA ++ + ++ ++ ++ ++ ++ - AMCHDA ++ + ++ ++ ++ ++ ++ - TCE: 1,1,2,2-tetrachloroethane ++: dissolved, +: dissolved upon heating, +-: partially dissolved,-: insoluble

As shown in Table 4, the PI resin of the present invention, unlike the conventional wholly aromatic PI, exhibited a very good dissolving ability in most organic solvents.

In the case of PI resin containing a rigid PMDA, it has been shown to be easily dissolved at room temperature in general organic solvents such as THF as well as aprotic solvents such as NMP, DMAc and DMF.

TABLE 5

Dissolution Characteristics of Hexafluoroisopropylidenediphthalic Acid (HFDA) PI Resin

Solvent Diamine Melting degree Dioxane THF CHCl ₃ CH ₂ Cl ₂ MEK Acetone EtOAc Acetonitrile CHDA ++ ++ ++ ++ ++ - - - MECHDA ++ ++ ++ ++ ++ ++ ++ - ETCHDA ++ ++ ++ ++ ++ ++ ++ - PHCHDA ++ ++ ++ ++ ++ -(?) -(?) - TBCHDA ++ ++ ++ ++ ++ ++ ++ - AMCHDA ++ ++ ++ ++ ++ ++ ++ - TMCHDA ++ ++ ++ ++ ++ ++ ++ - ++: dissolution, +: dissolution upon heating, +-: partial dissolution,-: insoluble

In addition, as shown in Table 5, in the case of the PI resin prepared using HFDA with increased flexibility of diacid anhydride, the solubility is increased, acetone, methyl ethyl ketone (MEK) or ethyl acetate It shows excellent solubility in commercial organic solvents such as (EtOAc). As a result, unlike the conventional wholly aromatic PI resin, the soluble PI resin according to the present invention shows excellent dissolving power even when polymerized with any kind of dianhydride. This is important for expanding the applicability of the PI resins of the present invention. That is, when the PI resin of the present invention is used as an adhesive material, it is excellent in dissolving power even in a completely imidized state, so that it can be manufactured into a PI film at a low temperature of 200 ° C. or lower, and the same as water when bonding by future heating. Since fewer by-products are generated, the generation of bubbles can be reduced. Thus, the PI resin of the present invention can be applied to a liquid crystal alignment film or a soluble photosensitive PI resin.

The PI resin of the present invention is not only excellent in heat resistance characteristics but also excellent in dissolution and melting characteristics, and thus can be applied as heat and insulation film of electrical and electronic parts, which require low temperature processing, and are useful as various advanced heat resistant structural materials.

Claims (6)

A polyimide resin characterized in that the following formula (1) as a repeating unit. Formula 1 In Chemical Formula 1, Is , , , And One or more tetravalent groups selected from among them; Is At least one substituted cyclohexylidene dianiline group represented by , , , , And Two groups selected from among them may be included; Wherein R ³ represents a phenyl group substituted by straight or branched alkyl group of C ₁ ~ C ₆ linear or branched alkyl group, a phenyl group, or C ₁ ~ C ₆ a. The polyimide resin according to claim 1, wherein the intrinsic viscosity of the polyimide resin is maintained in a range of 0.5 to 2.0 dL / g. The polyimide resin according to claim 1, wherein the polyimide resin maintains a molecular weight distribution in the range of 50,000 to 200,000 g / mol. The polyimide resin according to claim 1, wherein a glass transition temperature of the polyimide resin is 250 to 400 ° C. The method of claim 1, wherein the polyimide resin is dimethylacetamide, dimethylformamide N-methyl-2-pyrrolidone, acetone, ethyl acetateT, Tetrahydrofuran, chloroform, m-cresol and γ-butyrolactone A polyimide resin, characterized in that it is dissolved at room temperature with respect to a single solvent or two or more mixed solvents selected from. In the method of solution-polymerizing an aromatic tetracarboxylic dianhydride and an aromatic diamine compound, and manufacturing a polyimide resin, Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride (PMDA), benzophenone tetracarboxylic dianhydride (BTDA), oxydiphthalic dianhydride (ODPA), and biphenyltetracarboxylic dianhydride (BPDA). , One or two or more selected from hexafluoroisopropylidenediphthalic dianhydride (HFDA) and hydroquinone bisphthalic dianhydride (HQDPA), The aromatic diamine compound contains at least one of the substituted cyclohexylidene dianiline derivatives represented by the following formula (2) as an essential component, if necessary oxydianiline, methylene dianiline, metabisaminophenoxydiphenylsulfone and parabis A method for producing a polyimide resin having the following formula (1) as a repeating unit, characterized by containing one or two or more compounds selected from aminophenoxydiphenylsulfones. Formula 1 Formula 2 In the above formulas, , And R ³ are each as defined in claim 1.